1. Field of the Invention
This invention relates generally to portable beverage dispensing urns, or portable beverage dispensers, of the type having apparatus such as a faucet for dispensing the beverage and a top with an inlet for direct receipt of freshly brewed beverage from a coffee brewer or the like.
2. Discussion of the Prior Art
Portable beverage dispensers, or beverage dispensing urns, of the type having a top with an inlet for direct receipt of brewed beverage into a hollow, insulated urn body and a manually operable faucet at the bottom or other dispensing means for selectively dispensing beverage from the urn into a carafe or serving cups are well known. Some of the known portable beverage dispensers include a level indicating sight in the form of a glass, plastic or other transparent tube in fluid communication with the beverage in the container such that the level of the beverage within the sight corresponds to the level of the beverage within the hollow body of the urn. The sight and the level of the beverage in the sight is visible from outside of the dispensing urn to enable a user to determine the quantity of beverage contained within the urn without opening the top.
A serious problem with the tubular sights is that after use they become stained or coated with beverage residue. However, even though they must be regularly cleaned for purposes of sanitation and so that the residue does not contaminate and adversely affect the taste and quality of the beverage. Unfortunately, in know portable beverage dispensers the relatively small diameters and elongate body of the sight tubes renders it very difficult if not impossible to clean the sight tubes and their connections to the urn thoroughly without disassembly. Consequently, excessive time and labor is spent maintaining the urns in a sanitary condition or they are used in an unclean condition with resultant bad effects on the taste or quality of the beverage.
Because of this sanitation problem, such urns are not qualified for use with milk products that require higher standards of cleanliness than coffee dispensers because of the different nature of the beverages and the different potentials of harm resulting from lack of thorough cleaning. It is believed that there are no beverage dispensers with transparent tubular, level sights, or gauges, approved by the FDA, for use in dispensing milk and other milk products because of the inability to easily clean such level gauges.
In the case of a hot beverage, such as coffee, the temperature of the beverage decreases over time. In addition, the beverage also deteriorates over time due to contact with the air within the urn from the time it is first brewed directly into the dispensing urn and due to radiant heat loss through the sides of the hollow body of the beverage dispenser and also due to the heat loss caused by dispensing the beverage. In the case of cold drinks, such as ice tea or milk, the temperature gradually rises over time.
Generally, with the exceptions noted below, portable beverage dispensers lack any means for providing an indication of either beverage level, beverage temperature or elapsed time.
In U.S. Pat. No. 4,993,593 issued Feb. 19, 1991 to Fabiano et al. a hot soup dispenser is shown that has a temperature sensor, such as a thermistor, located adjacent the bottom of the hollow body at a low level mark. The temperature sensor is part of a temperature control system that includes an A.C. powered heating element to maintain the temperature between two selected maximum and minimum limits. When the beverage level falls beneath the low level mark, a change in temperature is detected to provide a single “LOW LIMIT” indication to advise an operator to add more soup. Unfortunately, this system is only guaranteed to work because the soup is being electrically heated to a temperature that is greater than the air within the hollow body of the soup dispenser. In an insulated beverage dispenser that lacks any means to heat the beverage, the hottest, or coldest, temperature exists when the beverage is first added to the dispenser and then gradually cools, or warms, to the ambient air temperature surrounding the dispenser. The air within the hollow body of the dispenser also degrades to the ambient air temperature, and when the temperature of the air within the hollow body equals the temperature of the beverage, there is no temperature differential sensed when the beverage falls beneath the low level mark. Also, the level sensor will not properly function with a beverage that is neither pre-heated nor pre-cooled. Moreover, since only the LOW LIMIT is indicated, there is not pre-warning of the beverage being depleted and no tracking of the gradual depletion of the beverage. In addition, of course, the soup dispenser is not portable because it requires a connection to an A.C. power outlet to maintain the hot temperature of the soup and thereby enable successful operation of the LOW LIMIT sensor and indicator. Because successful operation of the LOW LIMIT indicator relies upon connection of the soup dispenser to an AC power outlet, it fails to offer any solutions for a portable beverage dispenser that relies only on passive methods to maintain the temperature of the beverage.
In U.S. Pat. No. 4,290,537 issued Sep. 22, 1981 to Chi-Jung an air pot dispenser is shown with an insulated, non-electrically heated hollow body that is provided with a level indicator and a temperature indicator. Disadvantageously, the level indicator employs a mechanical float that must float in the beverage and is slidably attached to the discharge tube and thus cannot be fixedly connected to the level indicator that is mounted within the removable cap. The float remains in the hollow body of the airpot dispenser when the cap is removed to enable filling the airpot with beverage. The float and the linkage to the level indicator are apparently not readable removable for necessary cleaning of the interior of the airpot dispenser. Also disadvantageously, the temperature sensor does not measure the actual temperature of the beverage but instead only measures the temperature of the air, being “heated by the steam” within the hollow body located above the beverage and does not measure the temperature of the beverage, itself. Moreover, both of the indicators of level and temperature are mounted to an upwardly facing surface of a top closure cap and thus cannot be viewed by a user except when the viewer is located directly above the cap.
Beverage makers, such as coffee makers, that have hot water tanks with A.C. powered heating elements to maintain the temperature of the mixing water that is added to the ground coffee beans, of course, have temperature sensors that form part of the hot water temperature control system and the actual temperatures may be temporarily monitored for purposes of setting the limits and to determine whether the temperature control system is properly functioning or whether the limits have been correctly selected. An example of such a brewer is shown in U.S. Pat. No. 5,357,508 issued to Knepler et al. on Dec. 27, 1994. However, the hot water is only an ingredient that is added to another ingredient to make a beverage and not the beverage, itself, the brewer is not portable, but is bound to an A.C. power outlet.
In U.S. Pat. No. 5,229,751 issued Jul. 20, 1993 of Chandler et al an automatically actuated elapsed time timer is used to control display to indicate whether the beverage is “FRESH”, but this does not provide any actual condition of the beverage and this feature is only utilized with an insulated, transparent glass beaker with an open top from which the beverage is poured, and thus has no use for a level.